The present invention relates to a driving force transmission apparatus for driving a compressor into rotation with a motor, for example, upon engine stops such as idle stops of an automobile.
In this type of driving force transmission apparatus, it has conventionally been practiced that an electromagnetic clutch is provided, for example, between a rotating shaft for driving the compressor and a pulley for transmitting the rotation of the engine to the rotating shaft, where this electromagnetic clutch is kept ON during the rotation of the engine so that the rotational driving force is transmitted from the pulley to the rotating shaft, while the electromagnetic clutch is kept OFF during the stop of the engine so that the rotating shaft and the pulley are disconnected from each other, and the rotating shaft is driven into rotation with a motor.
However, this conventional driving force transmission apparatus, because of its needing an electromagnetic clutch as well as its on/off control, has had a problem of complicated structure.